TOXICITY OF ROTENONE AND DERRIS EXTRACT ADMINISTERED ORALLY TO BIRDS

¹ From the Department of Entomology, Cornell University, Ithaca, New York

The approximate oral rotenone toxicity values are given for twelve different species of nestling birds. The MLD was determined statistically for the Eastern Robin and English Sparrow nestling. The values were 0.195 and 0.199 mgm. per gram respectively. Data are presented showing that the MLD is higher in older individuals of the same species. This was found true with chickens, pheasants, English Sparrows, and probably Prairie Horned Larks. Chickens and pheasants, precocial birds, appear much more resistant to rotenone administered orally than nestling birds of the same age. Pigeon and Eastern Mourning Dove nestlings, intermediate in relationship between the precocial and other altricial birds, seem to be as susceptible to rotenone as the Passerine birds, indicating that the developmental stage is quite important in rotenone toxicity studies. Derris extract, containing 25% rotenone, was somewhat more toxic than crystalline pure rotenone when administered orally to five-day old chickens. Ground derris root containing 0.75% rotenone was nearly 25 times as toxic as pure rotenone when considered from rotenone content alone. It was given orally on various insect larvae to Robin nestlings. The possible dangers of rotenone to birds are discussed. Game birds appear to be in very little danger, while nestling birds could be poisoned under certain circumstances.